Live turret, as the name implies, is specifically driven by the CNC control and the turret of various spindle and powered sub-spindle configurations on CNC lathes to perform various operations while the workpiece remains in orientation to the main spindle. These devices, whether BMT or VDI, are also called driven tools, as opposed to the static tools used during turning operations. Live tools are usually customized for the particular machine tool builder’s turret assembly.
Most often, live tooling is offered in standard straight and 90º configurations with a variety of tool output clamping systems, including collet chuck, arbor, Weldon, Capto, whistle notch, hydraulic, HSK, CAT, ABS, and a variety of custom or proprietary systems developed by the many suppliers to the industry.
Investing in a Better Design
Bearing construction and the resulting spindle concentricity drive the life of any tool. A better design that costs just 10–15% more can yield both longer-lasting cutters and a consistently superior finish.
Of course, the stability and rigidity of the machine tool base are also critical factors, especially on large or deep-pocket workpieces where the distance from the tool base to the cutter tip is greater. Bevel and spur gears that are hardened, ground and lapped in sets are best for smooth transition and minimal runout. Roller bearings are consistently superior to spindle bearings in live tooling applications, so look for a combination system to get the highest possible precision. Also look for an internal vs. external collet nut so the tool seats more deeply in the tool. This produces superior rigidity.
Likewise, high-pressure coolant may be desirable. Look for 2000 psi (13.79 MPa) in 90º and 1000 psi (6.9 MPa) minimum in straight tools.
In a typical setup, the tools are mounted on a disc turret. With a face-mount version, the tools are located on the front of the tool-plate face; on a radial-mount or stair turret, the tools are arrayed on the OD of the tool plate. A servo in the turret powers tool indexing and operation. Driven by the CNC, with a wide range of possible spindles, sub-spindles, and tool holders, the live tools perform off-center operations while the workpiece remains oriented to the main spindle. ;
From the start, live tooling was added to increase a lathe’s usefulness. What many users of lathes and live tooling don’t realize is just how useful live tooling has become. State-of-the-art live tooling is versatile enough that it is applied even when the turning function of the lathe itself isn’t.
Other industry experts agree that a live-tooling system offers significant advantages. Frank Cerrito, general manager of Koma Precision Inc., East Windsor, Conn., put it succinctly, “The main reason customers invest in live tooling is that it allows them to do an operation that would have otherwise required another setup, off of the lathe. So it saves time and prevents possible errors.” ;
Leigh Bickham, product manager for Sauter and EWS live-tool distributor ITI Tooling Co. Inc., Ramsey, N.J., noted: “If you’re working on the OD of a part and you then need to mill a flat or drill and tap a hole, you can’t do that on a traditional static lathe. You’d have to move the part from the lathe to a mill. So, the idea behind live tooling was, ‘Let’s eliminate operations and make a turret that’s capable of handling drilling, tapping and milling.’ That’s the biggest advantage—eliminating setups and entire operations.”